The present invention relates generally to telecommunications systems, and more particularly, to systems and techniques for detecting a device that requires power.
Data terminal equipment (DTE) devices are well known. Examples of DTE devices include any kind of computer, such as notebooks, servers, and laptops; smart VCRs, refrigerators, or any household equipment that could become a smart device; IP telephones, fax machines, modems, televisions, stereos, hand-held devices, or any other conventional equipment requiring power. Heretofore, DTE devices have generally required external power from an AC power source. This methodology suffers from a number of drawbacks including interoperability during power shortages or failure of the external power source. Accordingly, it would be desirable to implement a system where the DTE power is drawn directly from the transmission line. This approach, however, would require a technique for detecting whether a DTE is connected to the transmission line and whether the DTE requires power.
In one aspect of the present invention, a power detection system includes a detector having an output and a return, and a device to selectively couple the detector output to the detector return when the device requires power.
In another aspect of the present invention, a detector having an output and a return includes a word generator coupled to the detector output, and a comparator to compare the detector output with the detector return.
In yet another aspect of the present invention, a method for detecting a device requiring power includes transmitting a pulse to the device, receiving the pulse from the device, and detecting whether the device requires power in response to the received pulse.
In yet still another aspect of the present invention, a transmission system includes a transmission line interface having at least one port, a two-way transmission line coupled to one of the ports, and a device coupled to the differential transmission line, the device selectively coupling the two-way transmission line together when the device requires power.